RBP: 0000000000000082 R08: 0000000000000001 R09: 0000000000400037
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000404810 R14: 0000000000000000 R15: 0000000000000000
8021q: adding VLAN 0 to HW filter on device batadv0
==================================================================
BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:673 [inline]
BUG: KASAN: use-after-free in qdisc_class_hash_insert+0x417/0x430 net/sched/sch_api.c:716
Write of size 8 at addr ffff880118801250 by task syz-executor831/12392

CPU: 1 PID: 12392 Comm: syz-executor831 Not tainted 4.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x145/0x1e1 lib/dump_stack.c:52
 print_address_description.cold.7+0x9/0x1c9 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report.cold.8+0x121/0x2da mm/kasan/report.c:408
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:434
 hlist_add_head include/linux/list.h:673 [inline]
 qdisc_class_hash_insert+0x417/0x430 net/sched/sch_api.c:716
 qfq_change_class+0x8b4/0x126f net/sched/sch_qfq.c:502
 tc_ctl_tclass+0x3c9/0xc60 net/sched/sch_api.c:1696
 rtnetlink_rcv_msg+0x4c0/0x7e0 net/core/rtnetlink.c:4216
 netlink_rcv_skb+0x211/0x490 net/netlink/af_netlink.c:2397
 rtnetlink_rcv+0x25/0x30 net/core/rtnetlink.c:4222
 netlink_unicast_kernel net/netlink/af_netlink.c:1265 [inline]
 netlink_unicast+0x426/0x630 net/netlink/af_netlink.c:1291
 netlink_sendmsg+0x8c3/0xe80 net/netlink/af_netlink.c:1854
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xb5/0xf0 net/socket.c:643
 ___sys_sendmsg+0x2a7/0x9a0 net/socket.c:2037
 __sys_sendmmsg+0x1ae/0x590 net/socket.c:2127
 SYSC_sendmmsg net/socket.c:2158 [inline]
 SyS_sendmmsg+0xd/0x20 net/socket.c:2153
 entry_SYSCALL_64_fastpath+0x23/0xc2
RIP: 0033:0x447569
RSP: 002b:00007ffddf02be88 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000447569
RDX: 0000000004924b68 RSI: 0000000020000140 RDI: 0000000000000006
RBP: 0000000000000082 R08: 0000000000000001 R09: 0000000000400037
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000404810 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 12355:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x14b/0x7a0 mm/slab.c:3627
 kmalloc include/linux/slab.h:492 [inline]
 kzalloc include/linux/slab.h:665 [inline]
 qfq_change_class+0x64a/0x126f net/sched/sch_qfq.c:476
 tc_ctl_tclass+0x3c9/0xc60 net/sched/sch_api.c:1696
 rtnetlink_rcv_msg+0x4c0/0x7e0 net/core/rtnetlink.c:4216
 netlink_rcv_skb+0x211/0x490 net/netlink/af_netlink.c:2397
 rtnetlink_rcv+0x25/0x30 net/core/rtnetlink.c:4222
 netlink_unicast_kernel net/netlink/af_netlink.c:1265 [inline]
 netlink_unicast+0x426/0x630 net/netlink/af_netlink.c:1291
 netlink_sendmsg+0x8c3/0xe80 net/netlink/af_netlink.c:1854
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xb5/0xf0 net/socket.c:643
 ___sys_sendmsg+0x2a7/0x9a0 net/socket.c:2037
 __sys_sendmmsg+0x1ae/0x590 net/socket.c:2127
 SYSC_sendmmsg net/socket.c:2158 [inline]
 SyS_sendmmsg+0xd/0x20 net/socket.c:2153
 entry_SYSCALL_64_fastpath+0x23/0xc2

Freed by task 12355:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x270 mm/slab.c:3820
 qfq_change_class+0xdb5/0x126f net/sched/sch_qfq.c:531
 tc_ctl_tclass+0x3c9/0xc60 net/sched/sch_api.c:1696
 rtnetlink_rcv_msg+0x4c0/0x7e0 net/core/rtnetlink.c:4216
 netlink_rcv_skb+0x211/0x490 net/netlink/af_netlink.c:2397
 rtnetlink_rcv+0x25/0x30 net/core/rtnetlink.c:4222
 netlink_unicast_kernel net/netlink/af_netlink.c:1265 [inline]
 netlink_unicast+0x426/0x630 net/netlink/af_netlink.c:1291
 netlink_sendmsg+0x8c3/0xe80 net/netlink/af_netlink.c:1854
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xb5/0xf0 net/socket.c:643
 ___sys_sendmsg+0x2a7/0x9a0 net/socket.c:2037
 __sys_sendmmsg+0x1ae/0x590 net/socket.c:2127
 SYSC_sendmmsg net/socket.c:2158 [inline]
 SyS_sendmmsg+0xd/0x20 net/socket.c:2153
 entry_SYSCALL_64_fastpath+0x23/0xc2

The buggy address belongs to the object at ffff880118801240
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 16 bytes inside of
 128-byte region [ffff880118801240, ffff8801188012c0)
The buggy address belongs to the page:
page:ffffea0004620040 count:1 mapcount:0 mapping:ffff880118801000 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff880118801000 0000000000000000 0000000100000015
raw: ffffea000456d320 ffffea0004a8ee20 ffff88012bc00640 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff880118801100: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff880118801180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff880118801200: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                 ^
 ffff880118801280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff880118801300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================